Video conference calls can be made using a wide variety of devices, such as office video conferencing systems, personal computers, and telephone devices including mobile telephones. Thus, video conferencing can be used at many different locations, including company offices, private residences, Internet cafés and even on the street. The many possibilities and varied locations for holding video conferences can create a problem since the video conference camera reveals the location of the participant to all those watching or participating in the video conference. For instance, if a video conference call is made from a participant's private place of residence, the participant's privacy may be compromised since the participant's private environment and members of his or her household may be exposed and photographed during the video conference call. It is desired to be able to maintain the privacy and confidentiality of other commercial issues that may inadvertently otherwise appear in the background of a video conference. It is desired to have a technique that ensures that such items will not be revealed or shared during the video conference.
Range measurement is important in several applications, including axial chromatic aberration correction, surveillance means, and safety means. Active methods for calculating the distance between an object and a measuring apparatus are usually based on the measurement of the time required for a reflected electro-magnetic or acoustic wave to reach and be measured by measuring apparatus, e.g., sonar and radar. Active methods of range measurement are detrimentally affected by physical objects present in the medium between the measuring apparatus and the object. Current passive methods use an autofocus mechanism. However, determining the range typically involves varying the focal length by changing lens position, which is not available in camera phones and many other camera-enabled devices.
Digital cameras are usually equipped with iris modules designed to control exposure, which are based on a detection result received from the sensor. Due to size and cost limitations, camera phones usually have fixed apertures and, hence, fixed F numbers. Existing mechanical iris modules are difficult to even incorporate in their simplest form into camera phones due to increased price of optical module, increased form factor since the iris module height is about 1 mm, greater mechanical sensitivity, consumption of electrical power, and complex integration (yield).
Digital cameras are usually equipped with iris modules designed to control exposure, which is based on a detection result received from a sensor. Due to size and cost limitations, camera phones usually have fixed apertures and, hence, fixed F numbers. Mobile phone cameras commonly have apertures that provide F numbers in the range of F/2.4-F/2.8. An advantage of the higher value, F/2.8, is mainly in its image resolution, but a drawback can be low performance under low light conditions. The lower value, F/2.4, compromises depth of focus and image resolution for a faster lens, i.e., better performance under low light conditions. Alternatively, a ND filter may be used to control exposure instead of changing F/#. Several high-end modules address the above-mentioned problems using mechanically adjustable apertures. Incorporating iris modules into camera phones offers a variable F number and achieves multiple advantages, including image quality improvement due to reduced motion blur, improved SNR and improved resolution. In addition, incorporation of iris modules into camera phones can tend to impart a digital still camera like “feel” due to the variable depth of field, i.e. Bokeh effect. Disadvantages of incorporating iris modules into camera phones include the increased price of the optical module, increased form factor due to the iris module height being about 1 mm, greater mechanical sensitivity, consumption of electrical power, and complex integration (yield). It is desired to have a digital iris that enables the user to enjoy the advantages of the mechanical iris without its disadvantages and to experience the “feel” of a digital still camera.